Scientists have announced yesterday that a collaboration consisting of ETH Zurich, IBM Research, the Interstat University of Applied Sciences Buchs and Airlight Energy is to develop an affordable photovoltaic system capable of concentrating solar radiation 2,000 times and converting 80 percent of the incoming radiation into useful energy. The system can also provide desalinated water dan cool air in sunny, remote locations where they are often in short supply.
Based on a study by the European Solar Thermal Electricity Association and Greenpeace International, technically, it would only take two percent of the solar energy from the Sahare Desert to supply the world's electricity needs. Unforunately, current solar technologies on the market today are too expensie and slow to produce, require rare Earht minerals and lack the efficiency to make such massive installations practical.
The so-calle "High Concentration Photovotaic Thermal" (HCPVT) system uses a large parabolic dish made from multitude of mirror facets, which are attached to a sun tracking system. The tracking system positions the dish at the best angle to capture the sun's rays, which then reflect off the mirrors onto several microchannel-liquid cooled recievers with triple junction photovoltaic chips each 1x1 centimeter chip can convert 200-250 watts, on average, over a typical eight hour day in a sunny region.
The entire receiver combines hundreds of chips and provides 25 kilowatts of electrical power. The photovoltaic chips are mounted on microstructured substrates that pipe liquid coolants within a few tens of micrometers from the chip to absorb the heat and draw it away 10 times more effectivily than with passive air cooling.